The present invention relates to a method and apparatus in which a baffle plate is disposed in an open central space in a mold structure to retard the transfer of heat from article molds.
A mold structure having a plurality of article molds disposed in an array with an open central space is disclosed in U.S. Pat. No. 3,810,504, issued May 14, 1974 and entitled "Method for Directional Solidification". The apparatus disclosed in this patent includes an annular chill plate. A baffle plate is disposed in the open central space to retard the transfer of heat from the article molds to the chill plate. The baffle plate is slightly smaller than an opening in the base of the mold structure to enable the mold structure to be moved into and out of a furnace on the annular chill plate.
A mold structure having a plurality of article molds disposed in an array with an open central space is also disclosed in U.S. Pat. No. 4,673,021, issued Jun. 16, 1987 and entitled "Method and Apparatus for Casting Articles". This patent discloses the concept of obtaining a large temperature gradient with a baffle which blocks the radiation of heat from an open central space in an array of article molds as they are withdrawn from a furnace. The baffle is supported from a gating system by a support post which extends downwardly from the gating system. The construction of the gating system is complicated by the necessity of forming the baffle with its support post extending from the gating system.
The mold of the aforementioned U.S. Pat. No. 4,673,021 has an annular base plate which is connected with the lower end portions of the article molds to provide a stable base for the article molds. The base plate interconnects the article molds and holds them against movement relative to each during the casting of articles. In addition, the base plate enables a fluid tight seal to be obtained between open lower end portions of the article molds and a chill plate. In order to obtain a stable mold structure and to obtain a fluid tight seal between the open lower end portions of the article molds and the chill plate, it is advantageous to make the base plate relatively wide.
A mold structure having an open central space in which a baffle plate is disposed is disclosed in U.S. patent application Ser. No. 13,469, filed Feb. 11, 1987 by Lawrence D. Graham et al., and entitled "Apparatus and Method for Use in Casting Articles". This application discloses the concept of supporting a baffle plate in the open central space between article molds with a support structure which extends through a chill plate.